In the previous grant period we developed the use of synthetic oligodeoxyribonucleotides as probes for the isolation of cloned DNAs coding for proteins of or related to the major histocompatibility complex (MHC). We have isolated cDNA clones for human Beta2-microglobulin and H-2Kb related molecules. In this grant we propose to extend our efforts to the isolation of cloned DNAs (both cDNA and genomic DNA) of human Ia antigens coded for by the HLA-D region. The specific objectives are: 1. Isolation and the complete sequence of cDNA clones for several Ia antigens in order to gain the structural information. 2. Isolation of genomic clones for those Ia antigens for which cDNA clones have already been obtained. 3. To find any difference in these Ia antigens between normal individuals and insulin dependent diabetes patients by restriction fragment lenghth polymorphism analysis.